/*
 * Copyright (c) 2011-2022, baomidou (jobob@qq.com).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.github.yulichang.toolkit.support;

import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.core.toolkit.ReflectionKit;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

/**
 * 在 IDEA 的 Evaluate 中执行的 Lambda 表达式元数据需要使用该类处理元数据
 * <p>
 * Create by hcl at 2021/5/17
 */
public class IdeaProxyLambdaMeta implements LambdaMeta {
    private static final Field FIELD_MEMBER_NAME;
    private static final Field FIELD_MEMBER_NAME_CLAZZ;
    private static final Field FIELD_MEMBER_NAME_NAME;

    static {
        try {
            Class<?> classDirectMethodHandle = Class.forName("java.lang.invoke.DirectMethodHandle");
            FIELD_MEMBER_NAME = ReflectionKit.setAccessible(classDirectMethodHandle.getDeclaredField("member"));
            Class<?> classMemberName = Class.forName("java.lang.invoke.MemberName");
            FIELD_MEMBER_NAME_CLAZZ = ReflectionKit.setAccessible(classMemberName.getDeclaredField("clazz"));
            FIELD_MEMBER_NAME_NAME = ReflectionKit.setAccessible(classMemberName.getDeclaredField("name"));
        } catch (ClassNotFoundException | NoSuchFieldException e) {
            throw new MybatisPlusException(e);
        }
    }

    private final Class<?> clazz;
    private final String name;

    public IdeaProxyLambdaMeta(Proxy func) {
        InvocationHandler handler = Proxy.getInvocationHandler(func);
        try {
            Object dmh = ReflectionKit.setAccessible(handler.getClass().getDeclaredField("val$target")).get(handler);
            Object member = FIELD_MEMBER_NAME.get(dmh);
            clazz = (Class<?>) FIELD_MEMBER_NAME_CLAZZ.get(member);
            name = (String) FIELD_MEMBER_NAME_NAME.get(member);
        } catch (IllegalAccessException | NoSuchFieldException e) {
            throw new MybatisPlusException(e);
        }
    }

    @Override
    public String getImplMethodName() {
        return name;
    }

    @Override
    public Class<?> getInstantiatedClass() {
        return clazz;
    }

    @Override
    public String toString() {
        return clazz.getSimpleName() + "::" + name;
    }

}
